0.5 \cdot \sqrt{2 \cdot \left(\sqrt{re \cdot re + im \cdot im} - re\right)}\begin{array}{l}
\mathbf{if}\;re \le -4.1094940511471951 \cdot 10^{119}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(-2 \cdot re\right)}\\
\mathbf{elif}\;re \le -1.3723278512607863 \cdot 10^{-307}:\\
\;\;\;\;0.5 \cdot \sqrt{2 \cdot \left(\sqrt{1} \cdot \sqrt{re \cdot re + im \cdot im} - re\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{\sqrt{2 \cdot {im}^{2}}}{\sqrt{\sqrt{re \cdot re + im \cdot im} + re}} \cdot 0.5\\
\end{array}double f(double re, double im) {
double r17576 = 0.5;
double r17577 = 2.0;
double r17578 = re;
double r17579 = r17578 * r17578;
double r17580 = im;
double r17581 = r17580 * r17580;
double r17582 = r17579 + r17581;
double r17583 = sqrt(r17582);
double r17584 = r17583 - r17578;
double r17585 = r17577 * r17584;
double r17586 = sqrt(r17585);
double r17587 = r17576 * r17586;
return r17587;
}
double f(double re, double im) {
double r17588 = re;
double r17589 = -4.109494051147195e+119;
bool r17590 = r17588 <= r17589;
double r17591 = 0.5;
double r17592 = 2.0;
double r17593 = -2.0;
double r17594 = r17593 * r17588;
double r17595 = r17592 * r17594;
double r17596 = sqrt(r17595);
double r17597 = r17591 * r17596;
double r17598 = -1.3723278512607863e-307;
bool r17599 = r17588 <= r17598;
double r17600 = 1.0;
double r17601 = sqrt(r17600);
double r17602 = r17588 * r17588;
double r17603 = im;
double r17604 = r17603 * r17603;
double r17605 = r17602 + r17604;
double r17606 = sqrt(r17605);
double r17607 = r17601 * r17606;
double r17608 = r17607 - r17588;
double r17609 = r17592 * r17608;
double r17610 = sqrt(r17609);
double r17611 = r17591 * r17610;
double r17612 = 2.0;
double r17613 = pow(r17603, r17612);
double r17614 = r17592 * r17613;
double r17615 = sqrt(r17614);
double r17616 = r17606 + r17588;
double r17617 = sqrt(r17616);
double r17618 = r17615 / r17617;
double r17619 = r17618 * r17591;
double r17620 = r17599 ? r17611 : r17619;
double r17621 = r17590 ? r17597 : r17620;
return r17621;
}



Bits error versus re



Bits error versus im
Results
if re < -4.109494051147195e+119Initial program 55.2
rmApplied add-sqr-sqrt55.2
Applied sqrt-prod55.2
Taylor expanded around -inf 9.8
if -4.109494051147195e+119 < re < -1.3723278512607863e-307Initial program 20.1
rmApplied add-sqr-sqrt20.1
Applied sqrt-prod20.2
rmApplied *-un-lft-identity20.2
Applied sqrt-prod20.2
Applied associate-*l*20.2
Simplified20.1
if -1.3723278512607863e-307 < re Initial program 46.2
rmApplied flip--46.1
Applied associate-*r/46.1
Applied sqrt-div46.2
Simplified35.4
Final simplification26.1
herbie shell --seed 2020042
(FPCore (re im)
:name "math.sqrt on complex, imaginary part, im greater than 0 branch"
:precision binary64
(* 0.5 (sqrt (* 2 (- (sqrt (+ (* re re) (* im im))) re)))))